Indicating means for high-frequency oscillations



suzasmm 170 MI SL E 33,

Dec. 2. 1930.

Filed March 11. 1927 INIENTOR ALEXANDER MEISSNER A2 ORNEY 1783297 QR T 324/109 Patented Dec. 2, 1930 a r-urea sra'rss ALEZA'LJDEB 152155333, 0! BERLIN, GEE-HAW, ASSIGNOB TO GIEELLSCHAIET FU'B DEAETLC'SE TELIGZAPHIE, H. 3. 3., OF BIBLE, GER-MARY, A GOBEOBA'I'ION OIE' cams? IHDIQAIISG ms FOB. HIGH-FREQUENCY OSCILLATIQNE Application filed we 11, 1921; Serial L lo.

This invention relates broadly to a novel and useful energy translati g system and more particularly to a system which is adapted to indicate the deformation caused in piezo-electric crystals when sihjected to the action of high frequency currents.

One of the objects of we present invention is to disclose means ad ted to directly convert high-frequency ene.gy into mechanical energy. This is accomplished by the agency of a iezo-electric crystal which, when excited oy hi h-frequency oscillations, oscillates in a we lknown manner.

Another object of the present invention is to transcribe thesecszfillations so as to be more easil readable.

Other 0 jects will he apparent when the following description and claims are read in connection with the accompanying drawings wherein,

Fig. 1, shows a piezo-electric crystal in a circuit ready to receive electrical impulses;

Fig. 2, is a plan crosssection view of the crystal taken along line 2-2 of F lg. 1 and shows the apparent region of air eddy currents produced when the crystal is vibratigure 3.represent-s a schematic arrangement of my invention adapted for indicating and recording.

Fig. 4 shows diagrammatically the faces of the crystal which undergo certain physical changes for purposes of this invention.

Referring to Fig. 1, let K be a. piezo-electric crystal which is caused to oscillate at its own natural period by the action of a high frequency oscillation transierred or fed to it from circuit I consisting of condenser C and an inductance D for receiving the energy. On the sides of the said crystal, one can then observe violent air eddies which, rs it were, are excited by the acoustic oscillations of the crystal. II lycopodium powder is strewn around a crystal under these conditions, it is found that the said powder is blown away at points 1, 2, 3, 4 (Fig. 2), which goes to indicate that energy fluxes issue from the said points. Now, in accordance with the pment invention, it is these 174,804, and in Germany Batch 25, 182B.

energy fluxes that are used for the purpose of acting upon an indicator.

More specifically, Fig. 2 shows the formation of flow at a crystal which oscillates insure exerted by said flows. In Fig. 2 the cross-hatched triangles represent or connect points of equal intensity of air current at difierent distances from the crystal.

The air flow is more or less steady and originates, as it were, from acoustic rectification. One possible explanation of this phenomena would be that the over pressures at acoustic excitation which ori note from the surfaces of the crystal, mani est themselves. However, the partial vacua does not because of the fact that fresh air particles flow in from all directions. The flow might be said to consist of constituent or separate high frequency shocks according to the movement or oscillations of the crystal.

- In Fig. 2 in order that the phenomena referred to take place as shown, the usual electrode would have to be mounted at right angles to the electrical axis of the crystal, that is, looking at Fig. 2, above and below the plane of the drawing. The air currents in eve case are at right angles to the line connectmg the two electrodes.

Fig. 4 more clearly shows a crystal of a shape such that onlv two pronounced air currents will be produced. in Fig. 4 when the crystal is excited air currents arise at the two lateral faces A and B, that is to say, that the surfaces by virture of piezo-electric crystal action under 0 acoustic vibrations or motions at high equency.

The electrodes in. .his case are arranged at the surfaces 1, 2, 3, 4 and 5, 6, 7, 8.

Another scheme would be to place a. mirror M (Fig. 3) in the path of the energy flux at the crystal, said mirror being used to con- 1W trol a. luminous ray from lamp L by virtue of the vibrations occasioned by the hi h frequency energy; the ray would in turn pro- Jected upon a screen or on a photographic tape, Fi 3 shows a means of securing the mirror 181% It is preferable as stated before to use for such a mirror arrangement a. crystal which has only two pronounced air currents. Also, in orderto correctly obtain the m rotary effect on the mirror, one half of the mirror would have to be screened or covered from the air currents. It is to be noted that the crystal may be supported between the electrodes by any suitable bearing device dependent on the conditions desired. In brief, the ener y produced in the oscillating crystal by action of the high frequency energy can be utilized in any desired manner.

To further improve ihe effects attainable according to the resent method, the mechanical vibration ody can he placed within a confined space kept at raised gas or air pressure thereby increasing the efficiency of the device. Having thus described my invention what I desire to protect by Letters Patent is:

LA method for indicating the intensity of' oscillations of high frequency energy I which consists in measuring the extent of air disturbances occasioned in the immediate vicinity of a piezo electric crystal device while the latter is subjected to the effect of high frequency energy. a v 2. A' method for indicating the intensity of oscillations of electrical energy applied to an electrical circuit which consists in measuring the extent of disturbances in a g medium surrounding a piezo-electric crystal device when the latter is subjected to the 'j 40 effect of said energy. '3. A device adapted to indicate the intensity of oscillations applied to an electrical circuit comprising in combination a piezo-electric crystal oscillation system and 5 means adjacent one of the faces of the piezoelectric crystal adapted to respond to air disturbances occasioned in the immediate vicinity of said crystal when said crystal is subjected to the eifect of electrical energy. 4. In a device for indicating the extent of deformation resulting in a piezo-electric crystal when subjected to the action of high frequenc oscillations in combination, a piezoelectric crystal surrounded by a medium, an oscillation circuit operatively associated with said or stal and means for measuring the ex- 5 tent o disturbances occasioned to said medium in the immediate vicinity of said piezoelectric crystal when said crystal is subJccted '60 to high frequency energy.

ALEXANDER MEISSNER. 

